全面二維氣相層析應用於空氣與生活複雜樣品之分析

Application of vapor and liquid phase real samples by 2D-GC(GC×GC)

周裕傑(Yu-chieh Chou)

指導教授 ： 王家麟

國立中央大學/理學院/化學系/碩士(2012年)

摘要

本次研究主要分為兩部分，第一部分為GC x GC – ECD，由於大氣中的鹵碳化合物濃度分布很廣(幾pptv至數百pptv)，因此必須透過濃縮方法提高有效濃度，以降低分析偵測極限，有鑑於此，本研究以自製前濃縮系統，內含自行填充吸附管以捕捉大氣中的鹵碳化合物，再以熱脫附方式注入全面二維層析系統分析；系統組裝採便利、易修繕、造價便宜、不需冷劑等優點的自製閥件型調制器(丁式切換器)，以脈衝( pulsed )方式將一維管柱( pre-column )沖堤物送入二維管柱( analytical column )作快速分離；資料以繪圖軟體( SurferR 8 )處理成三維結果；實驗由多種管柱搭配和最佳化調整後，成功以DB-5 x TG-1301組合能有效分離鹵碳化合物，此套系統的RSD值可低於0.94%，並以NOAA標準品定性定量各物種的實際濃度，而各物種的譜峰線性( R2 )也可達0.99以上，最後以此系統對大氣中的物種做連續監測，並可得良好效果；第二部分為GC x GC – FID，利用注射埠搭配雙火焰離子偵測器， DB-5 x DB-1701的管柱組合能成功對香水、精油、汽油、生質燃油和酒品作有效的分析，並藉由全面二維圖譜可發現，圖譜間的差異性相當明顯，可作為指紋圖譜資料庫的建立依據，若未來分析相同種類樣品時即可作為對照，以辨別樣品的來源和種類，若搭配定性功能極佳的質譜儀( GC x GC / ToF-MS )，也能針對特定物種進行定性探討。

關鍵字

全面二維氣相層析

並列摘要

This study consists of two objectives: one is to develop a GC x GC method with electron capture detection ( ECD ) to analyze trace levels ( ~pptv ) of atmospheric halocarbons, the other is to analyze complex liquid samples by GC x GC with flame ionization detection ( FID ).
To analyze atmospheric halocarbons a self-built pre-concentrator was employed for in-line enrichment before analyzed by GC x GC – ECD. To further lower the detection limits of chlorofluorocarbon ( CFC ) replacements, oxygen doping technique was adopted for electron capture detection. The GC x GC used a valve type modulator based on the Deans switch method. Analytes after eluting from the first column were cut into slices and sent to the second column for two-dimensional separation. A commercially available software, SuferR 8, was used to process the data into three-dimensional concentration contour plots. The column combination of DB-5 x TG-1301 was found to show the best separation results for halocarbons. The correlation coefficients ( R2 ) of 2D vs. 1D results were greater than 0.9920. The reproducibility ( RSD based on N = 30 ) was better than 0.94% for all target halocarbons. The method can be used in either online or offline mode. Flask samples can be analyzed when the system is operated in off-line mode, whereas continuous monitoring is possible when the system is operated in on-line mode.
As the second objective to analyze complex liquid samples, such as perfume, essential oil, wine, gasoline and biofuel, etc. the Deans switch GC x GC – FID method was tested. The column combination of DB-5 x DB-1 was found to show the optimal separation results. Rather than pursuing full separation as with the halocarbon analysis, the concept of “pattern recognition” of complex samples was adopted. A product series with minor composition variation can be distinguished based on pattern difference. This application is found particular useful where imitating products can be easily separated apart from their genuine counterparts. When compare the self-made GC x GC – FID method with the commercial GC x GC / ToF-MS method using the identical column combination, compound identification becomes possible, which further broadens the applicability of the proposed method.

並列關鍵字

2D-GC (GC×GC)

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